I can think of good comebacks but the problem with me is that I can't phrase it properly since English is not my primary language. For example: If someone shows me his family tree which is big and have famous/successful peoples, I can reply "I am an environmentalist, a great one but trees like this are better being cut down", something like this but it sounds pretty lame and can be turned into a good one with rephrase. Give ur best advice (open for constructive criticism).